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Long-term effect of nutrient management and cropping system on cotton yield and soil fertility in rainfed vertisols

Venugopalan, M.V., Pundarikakshudu, R.
Nutrient cycling in agroecosystems 1999 v.55 no.2 pp. 159-164
Gossypium hirsutum, Gossypium arboreum, cropping systems, crop management, soil fertility, crop yield, Vertisols, dryland farming, nitrogen, phosphorus, potassium, field experimentation, crop rotation, Sorghum bicolor, soil organic matter, nutrient availability, harvest index, nitrogen fertilizers, phosphorus fertilizers, potassium fertilizers, application rate, animal manures, continuous cropping, India
The effect of different N, P and K combinations with and without FYM on cotton productivity and the changes in soil fertility of three rainfed cotton based cropping systems were analyzed through a field experiment, conducted for 11 yr. Monoculture of G. arboreum (Asiatic cotton, out-yielded monoculture of G. hirsutum (upland) cotton in 9 out of 11 yr, except in years of heavy rainfall. G. hirsutum cotton in rotation with sorghum produced 8% more yield than monocultured G. hirsutum. Significant responses to N and P application were consistently observed, while the response to K was inconsistent. Substituting half the N dose with FYM, gave 162 kg/ha and 222 kg/ha more seed cotton at low (N60 P13 K25) and high (N90 P20 K38) doses respectively. Also substituting half the N dose with FYM built up soil organic C from 4.2 to 5.4 g/kg, and increased available P from 4.5 to 6.4 mg/kg. The variations in the performance of the cropping systems and the response to fertilizers could not be accounted for by total rainfall alone. However, there was significant positive correlation between cotton yield and post September rainfall. Multiple regression equations were fitted to estimate G. arboreum and G. hirsutum yields based on the monthly distribution of rainfall.